I. Field of the Invention
The present invention relates to a medical bag and a method for manufacturing the same, and more particularly, to an improvement in a medical bag formed from sheets which exhibit a blocking tendency at high temperatures.
II. Description of the Prior Art
Flexible medical bags such as blood bags are currently made of soft polyvinyl chloride or polyolefin-type resins. These medical bags must be sterilized (generally sterilized by steam autoclaving) for hygiene. However, the resins as described above exhibit a blocking tendency at high temperatures during sterilization; the inner surfaces of the sheets of these resins adhere to each other. In order to solve this problem, sterilization is conventionally performed while introducing air into the bag. However, this results in poor workability.
If a blood bag is made of polyvinyl chloride, it is possible to add a substance which acts as an anticoagulant for platelets to polyvinyl chloride, and to transfer this substance to the inner and outer surfaces of the bag. However, this method does not provide sufficiently good results. Furthermore, when these measures are taken, elution of a plasticizer, which is a factor in degrading the storage characteristics of the platelets cannot be prevented. Other measures must be taken to prevent elution of the plasticizer.